Content uploaded by Ashutosh Sharma
Author content
All content in this area was uploaded by Ashutosh Sharma on May 20, 2017
Content may be subject to copyright.
J. Microelectron. Packag. Soc., 23(4), 1-6 (2016) https://doi.org/10.6117/kmeps.2016.23.4.001
Print ISSN 1226-9360 Online ISSN 2287-7525
1
Recent Progress in Electroless Plating of Copper
Ashutosh Sharma1, Chu-Seon Cheon2 and Jae Pil Jung1,†
Dept. of Materials Science and Engineering, University of Seoul, 163, Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, Korea
Danyang Soltec Co. Ltd., 29, Mado-ro 660beon-gil, Mado-myeon, Hwaseong-si, Gyeonggi-do 18541, Korea
(Received December 9, 2016: Corrected December 12, 2016: Accepted December 14, 2016)
Abstract: In this article, the recent developments in electroless plating of copper, electroless bath formulation and effect
of plating parameters have been reviewed. Cyanide free electroless baths are now being developed and studied due to
the various environmental concerns. Various organic chemicals such as complexing agents, reducing agents, and additives
such as poly-alcohols and aromatic ring compounds have been added to copper plating baths for promising results. The
effects of various reducing and complexing agents, bath conditions like additives, bath pH, and composition have been
summarized. Finally the applications of the electroless plating of copper and latest developments have been overviewed
for further guidance in this field.
Keywords: Electroless, additives, plating, copper, complexing agents, temperature
1. Introduction
Electroless plating is known for hundreds of years. It is a
process of deposition of thin layer of metals, salts, oxides
and other compounds used in various industrial and tech-
nological applications. The deposition of precious metals
like gold and silver were already used in early civilizations.
Wurtz in 1844 discovered the first nickel electroless coat-
ing using hypophosphite as a reducing agent. Later in
1946, Brenner and Riddell developed the process and pro-
posed the operating conditions for the nickel electroless
plating. They included various reducing agents including
sodium hypophosphite to obtain a controlled nickel plating.
William Blum coined the term ‘Electroless’ for this auto-
catalytic process because of no need of supplying external
current into the electrolyte bath.1) In electroless technique,
a noble metal is deposited from its salt on a catalytic active
surface of a less noble metal. On the contrary the electro-
plating involves supply of an external current for reaction
to happen. Apart from composition and organic additives,
electroplating involves a number of parameters like cur-
rent, pulse type, frequency and duty cycle of pulse, etc.,
making the process more complex.2-7) While in electroless,
the reaction is catalyzed by employing a suitable reducing
agent which supplies the electron for reduction reaction
and metal is deposited over the substrate.1,8) The reactions
can be shown as below:
Metal ion (M+) + Reducing agent (Red)
→ Metal Deposited + Oxidized product (Ox) (1)
There are two reactions in electroless plating:
Metal deposition: M+ + e → M (1a)
Oxidation: Red + H2O → Ox + H+ + e (1b)
Here, M: Metal, e: electron, Red: Reducing agent, Ox:
Oxidized product
The process is electrolytic as well as electroless in nature
as shown in Fig. 1.
The thickness of electroless coatings can reach up to 10
to 200 µm. Electroless plating is more useful than electro-
plating, for example, the possibility of producing coatings
with uniform thickness, depositing material even in deep
recess/vias, ability to produce very thin layers, excellent
step coverage, independent of the sizes, shape or conduc-
tivity of the substrate and absence of need for electrical
contacting of wafers during deposition.9,10) Significant
advancement occurred in electroless plating of Cu, Ni, Au,
Ag, Pd, Sn, etc., for industrial applications, however, the
various operating parameters and bath conditions are not
fully understood.10)
Corresponding author
E-mail: jpjung@uos.ac.kr
©
2016, The Korean Microelectronics and Packaging Society
This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/
licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is
properly cited.
특집
:
Electroless Plating of Copper
2Ashutosh Sharma, Chu-Seon Cheon and Jae Pil Jung
마이크로전자 및 패키징학회지 제23권 제4호 (2016)
2. Electroless Copper Plating
Copper is one of the oldest element known in the history.
In Latin, copper is termed as cuprum the Iceland of Cyprus
dates back to 11000 years.11) In the late 18th century, cop-
per was picked up by many scientists like Ampere, Fara-
day and Ohm for their discoveries in electricity and mag-
netism. Pure copper is soft, malleable and ductile with very
high thermal and electrical conductivity.10,11) Electroless
copper coatings provide protection for common metal sur-
face exposed to corrosion and wear. Electroless copper is
the material of today. As a coating, it is used in several
industrial applications ranging from aerospace, automotive,
electronics, telecommunications, information technology,
food processing, beauty care products, nuclear engineering,
petrochemicals, plastics, power transmission, printing,
pump valves, textiles etc..12) Electroless copper is being
extensively used in microelectronics and packaging of
devices, for interconnects in ultra large scale integration
(ULSI), IC fabrication and EMI shielding because it
doesn’t require vacuums or high temperature for thin metal
film deposition due to their high conductivity, resistance to
electro migration and no requirement for vacuum and high
temperature.10-12)
3. Plating Baths
3.1. Traditional baths
Traditional electroless plating baths are based on reduc-
ing agents based on formaldehyde and its derivatives. This
type of baths have two major drawbacks, such as, (1) form-
aldehyde baths operates around alkaline pH values
(> 11).10,13) (2) Aldehydes are volatile, flammable and pose
health hazard to human beings. Aldehydes have significant
environmental impact and continuous exposure to formal-
dehyde causes severe skin rashes, eye infections, difficulty
in coughing and breathing.10-14)
To overcome these drawbacks, people have used many
electroless copper baths based on non-formaldehyde
chemicals, e.g., hypophosphite, sodium bisulfate (NaH-
SO3), glyoxylic acid, the sodium thiosulfate pentahydrate
(Na2S2O3·5H2O), borane-dimethylamine complex, Co(II),
Fe(II),15-23) etc. Sodium hypophosphite is most attractive
due to its excellent bath stability, easy control, and lower
cost. However, the hypophosphite may oxidize on prolong
storage and may lead to the reduction in deposit quality.
For, alkaline baths the oxidation of hypophosphite can be
minimized by the addition of catalytic ions like Ni2+ or
Pd2+ ions.19,21-24) This increases the efficiency of the pro-
cess but limits the conductivity of the deposits due to the
impurities of Ni and Pd incorporated.19)
3.2. Methyl sulphonic acid (MSA) baths
MSA baths are getting more attention in the formulation
of electrolytic baths in electroless as well as electroplating
deposition of metals. MSA is the reducing acid which min-
imizes the oxidation of the metal ions. Procell et al. discov-
ered that alkyl sulphonic acids form highly soluble metal
salts in water producing clear solutions.24) MSA based
baths become popular during 1980’s for different metal
plating baths and is an excellent choice for various plating
applications.1,8-11,25,26) MSA acid is a transparent liquid hav-
ing chemical formula CH3SO3H characterized by
(i) Transparent slight yellowish
(ii) Soluble in water and sparingly soluble in benzene
(iii) Insoluble in paraffins
(iv) High conductivity better than HCl and H2SO4
(v) Excellent stability
(vi) Less toxic and safe to handle
(vii) Biodegradable, easy disposal
The deposits produced from MSA baths are of high qual-
ity, high adhesion strength, smooth free from dendrites and
porosity. The superiority of MSA over other plating baths
arises due to the fact that it can be operated at room tem-
perature, excellent bath life and conductivity, and bio-
degradability.25,26)
3.3. Complexing Agents
The complexing agents in electroless copper baths are
very important for good quality deposits. Complexing agents
minimize the formation of copper to copper hydroxides
(Cu(OH)2) in alkaline pH range.17) Complexing agents sta-
Fig. 1. Schematic representation of electroless metal deposition.
Recent Progress in Electroless Plating of Copper 3
J. Microelectron. Packag. Soc. Vol. 23, No. 4 (2016)
bilized the baths and increases bath life. Addition of com-
plexing agents in a small quantity increases in plating rate.
The mixed potential theory of electroless plating states that
the overall reaction of the electroless copper process is
given by two following half-reactions:
Cathodic reaction:
Cu[L]x +2 +2e−
→ Cu + xL (2)
Anodic reaction:
2HCHO + 4OH− → 2HCOO− + H2 + 2H2O + 2e−
(3)
During the electroless process, the two reactions occur
simultaneously on a catalytic surface. The most common
complexing agents for electroless copper are Ethylenedi-
aminetetraacetic acid (EDTA), trisodium citrate, malic
acid, lactic acid, triethanolamine, sodium potassium tarta-
rate, etc..27-30) EDTA and sodium potassium tartrate have
been used extensively in traditional electroless copper
baths containing formaldehyde as a reducing agent. These
plating baths produce low plating rates due to the forma-
tion of the cupric complexes and the shift in reduction
potential toward negative values. Moreover, EDTA is non-
biodegradable and produces serious waste disposal prob-
lems.31) In last few decades, the use of Triethanolamine
(TEA) has been used to yield higher plating rates com-
pared to when using EDTA.32) However, high plating rates
are associated with poor bath stability and deposit quality.
Tartrate based chelates are used for low plating rate at low
temperature. Tartrates are easy to dispose during waste
treatment but are not suitable for high speed plating pro-
cesses. Other biodegradable chelating agents are polyols.
Polyols easily form chelates with Cu(II) ions in alkaline
medium. The examples include glycerol, xylitol, sacchar-
ose, alditol, erythritol, adonitol, D-mannitol, D-sorbitol,
maltitol, lacticol etc., for eco-friendly chelating agents for
alkaline electroless plating.33)
3.4. Reducing Agents
The role of reducing in electroless plating is most
important as it reduces the cupric ions (Cu2+) to metal
atoms copper (Cu) without any change to cuprous oxide
(Cu+). Traditional electroless copper plating baths often
use formaldehyde as the reducing agent.13) While using
formaldehyde, the electroless copper deposition can be rep-
resented as:
Cu2+ + 2HCHO- + 4OH-
→ Cu + 2HCOO- +2H2O +H2 (4)
However, formaldehyde is not completely effective in
alkaline pH values due to oxidation of the plating bath.14)
In addition, formaldehyde is volatile and toxic in nature.
Non-formaldehyde reducing agents used currently include,
glyoxylic acid], hypophosphite], sodium bisulfate (NaH-
SO3), sodium thiosulfate pentahydrate (Na2S2O3,5H2O),
Co(II),46) Fe(II) etc.16-22,27-32) Sodium hypophosphite is the
most popular reducing agent used in copper electroless
bath due to its low price, bath stability, and relatively easy
to control plating conditions.34) The electroless copper plat-
ing reaction using hypophosphite is given:
Cu2+ + 2H2PO2−
+ 2 OH- → Cu+ 2H2PO3- + H2 (5)
The catalytic activity of hypophosphite is weaker and
therefore the substrate must be prior activated with Pd or
Ni ions.17,19)
Glyoxylic acid as an alternative reducing agent for elec-
troless copper plating has been used by various researchers.
Glyoxylic acid provides higher plating rates and bath sta-
bility compared to that with formaldehyde reductant.14,15,35)
The overall reaction with glyoxylic acid is:
Cu2+ + 2CHOCOOH + 4OH-
→ Cu + 2HC2O4- + 2H2O +H2 ↑ (6)
CHOCOOH + 3OH-
→ HC2O4
− + 2H2O + 2e- + 1.01V/SHE (7)
This reaction is commonly accompanied by the Canniz-
zaro reaction,
2CHOCOOH + 2OH-
→ C2O42−
+ HOCH2COOH + H2O (8)
Other reducing agents investigated in electroless deposi-
tion of copper are Dimethylamine borane (DMAB), hydra-
zine, aminoborane and phenylhydrazine, but their applications
are limited due to bath stability and deposit quality optimi-
zations.22,36-38)
3.5. Additives
The additives are generally used to prevent decomposi-
tion of electroless baths. They behave as bath stabilizers.
Additives also affects the physical and mechanical proper-
ties of the deposit.27,38-40) There are various kinds of addi-
tives in electroless plating:
(a) Inhibitors: They are used to increase the throwing
power into holes and recess. e.g., polyethers or polyoxy-
ethers.
(ii) Levelers: Levelers improve plating thickness unifor-
mity at corners and projections and levels the plated layer,
e.g., amines, amide surfactants.
4Ashutosh Sharma, Chu-Seon Cheon and Jae Pil Jung
마이크로전자 및 패키징학회지 제23권 제4호 (2016)
(iii) Brighteners: Brighteners control deposit brightness
and hardness. They attach to the copper metal ions during
plating and facilitate charge transfer at the electrode.
Brighteners accelerate plating rates and also control grain
structure and deposit characteristics, e.g., Sulphur contain-
ing compounds.
(iv) Wetting agents: They decrease surface tension in
solution. Surfactants lower the surface tension of the plat-
ing solution and thus, allow better wetting of the electro-
lyte at the electrode.
The common additives in copper electroless plating baths
include thiourea, pyridine, cytosine, glycine, guanine, ade-
nine, guanine, ammonia, sodium dodecyl sulphate (SDS),
polyethylene glycol (PEG), mercapto group compounds,
benzo triazole (BTA), di-pyridyl etc. The additives are ben-
eficial in modifying crystal size, shape and orientation, and
adherent copper deposits.1,8-10,13-23)
3.6. Bath pH
Bath pH is an important parameter in electroless deposi-
tion. Bath pH controls the plating rate, microstructure, sur-
face roughness and the crystallinity of the coating.41)
Whenever there is an oxidation of the reducing agents, it
indicates the formation of hydrogen or hydroxyl ions
(OH−
). The bath pH should be stable for better efficiency
of the process. A change in pH severely affects the deposi-
tion rate during plating and hence the mechanical proper-
ties can get affected. To overcome unstable bath pH values,
various stabilizers such as NaOH, KOH, carboxylic acids
and amines are used in alkaline solutions.
4. Applications of Copper Electroless Plating
Last few decades have seen enormous growth and demand
of electroless copper plating in microelectronics packaging,
aerospace, automotives industries, etc. In advanced 3D
packaging technology, copper electroless plating is the
material of choice. Recently, electroless copper has been
tried for the functionalization of nanostructured materi-
als.13,14) Production of copper nano particles using hydra-
zine as reducing agent that have also been tried. Not only
metallic but also ceramics and polymers have been coated
with electroless copper in various engineering applica-
tions.13) Copper plating on polyamides, acrylonitrile butadi-
ene styrene, polyethylene terephthalate, polypropene, teflon,
films are flexible and used in modern flexible stretchable
electronics, PCBs and shielding applications.18)
Lightweight composites using the electroless copper
plating method. The pollen grains of the lightweight flow-
ers have been coated with copper electroless coating using
Pd catalyst.42,43) Substrates in solder joints for electronics,
multilayer boards via plated through-hole technique is per-
formed using electroless copper plating.44) Copper plated
ceramics are employed in microwave circuits in radar, tele-
communication and in spacecraft. Electroless plating is
important for various processes in electronic, computer,
and metallurgy industry of today.45,46)
5. Conclusion
The process of electroless copper coating on a substrate
is an autocatalytic reduction process. Copper electroless
plating uses a chemical bath composed of complexing
agents, reducing agents like hypophosphite and various
organic additives for better surface finish. The electroless
copper process has been successfully applied to various
surface protection, decorative, electronics, computers, infor-
mation technology, telecommunications and satellites. Elec-
troless copper applied on non-conducting base are used in
wide range of applications in modern flexible electronic
devices and sensors. It is concluded that a good fundamen-
tal background of copper electroless plating is needed to
understand the various roles of organic components in
electroless plating baths so that the properties of copper
coatings can be further improved considerable. This will
set a new direction for electroless plating in the modern
research community.
Acknowledgements
This work (Grants No. C0398999) was supported by
Business for Cooperative R&D between Industry, Acad-
emy and Research Institute funded Korea Small and
Medium business Administration in 2016.
References
1. B. Zhang, Amorphous and Nano Alloys Electroless Deposi-
tions, Technology, Composition, Structure and Theory, Else-
vier-Chemical Industry Press, USA (2016).
2. A. Sharma, S. Bhattacharya, S. Das and K. Das, “A Study on
the Effect of Pulse Electrodeposition Parameters on Surface
Morphology of Pure Tin Coatings”, Metall. Mater Trans. A,
45A, 4610 (2014).
3. A. Sharma, S. Das and K. Das, “Pulse Electroplating of Ultra-
fine Grained Tin Coating”, In: Electroplating of Nanostruc-
tures, M. Alioafkhazraei, Ed., InTech, Croatia (2015).
4. A. Sharma, K. Das, H. J. Fecht and S. Das, “Effect of Various
Additives on Morphological and Structural Characteristics of
Pulse Electrodeposited Tin coatings from Stannous Sulfate
Recent Progress in Electroless Plating of Copper 5
J. Microelectron. Packag. Soc. Vol. 23, No. 4 (2016)
Electrolyte”, App. Surf. Sci., 314, 516 (2014).
5. A. Sharma, S. Bhattacharya, S. Das and K. Das, “Fabrication
of Sn Nanostructures by Template Assisted Pulse Electrode-
position”, Surf. Eng., 32(5), 378 (2016).
6. A. Sharma, S. Bhattacharya, S. Das and K. Das, “Influence
of Current Density on Surface Morphology and Properties of
Pulse Plated Tin Films from Citrate Electrolyte”, App. Surf.
Sci., 290, 373 (2014).
7. A. Sharma, S. Bhattacharya, R. Sen, B. S. B. Reddy, H.-J.
Fecht, K. Das and S. Das, “Influence of Current Density on
Microstructure of Pulse Electrodeposited Tin Coatings”,
Mater. Charact., 68, 22 (2012).
8. M. Paunovic and M. Schlesinger, Fundamentals of Electro-
chemical Deposition, 2 ed., Joh Wiley & Sons (2006).
9. G. O. Mallory and J. B. Hajdu (eds), Electroless Plating: Fun-
damentals and Applications, American Electroplaters and
Surface Finishers Society, Orlando, Florida (1990).
10. M. Schlesinger, Modern Electroplating, 5th ed., John Wiley
& Sons Inc (2010).
11. Cuprum Copper Blue Vitriol, Actforlibraries.org (2016) from
http://www.actforlibraries.org/cuprum-copper-blue-vitrol/
12. J. R. Davis, “Copper and copper Alloys”, ASM Specialty
Handbook, ASM International, Materials Park, Ohio (2001).
13. J. F. Silvain, J. Chazelas and S. Trombert, “Copper Electroless
Deposition on NiTi Shape Memory Alloy: An XPS Study of
Sn-Pd-Cu Growth”, Appl. Surf. Sci., 153, 211 (2000).
14. H. Honma and T. Kobayashi, “Electroless Copper Deposition
Process Using Glyoxylic Acid as a Reducing Agent”, J. Elec-
trochem. Soc., 141, 730 (1994).
15. Y. Y. Shacham-Diamand, “Electroless Copper Deposition
Using Glyoxylic Acid as Reducing Agent for Ultra Large
Scale Integration Metallization”, Electrochem. Solid-State
Lett., 3, 279 (2000).
16. J. Li and P. A. Kohl, “The Acceleration of Nonformaldehyde
Electroless Copper Plating”, J. Electrochem. Soc., 149, C631
(2002).
17. A. Hung and K. M. Chen, Mechanism of Hypophosphite-
Reduced Electroless Copper Plating”, J. Electrochem. Soc.,
136 (1), 72 (1989).
18. Y. H. Chen, C. Y. Huang, F. D. Lai, M. L. Roan, K. N. Chen
and J. T. Yeh, “Electroless Deposition of the Copper Sulfide
Coating on Polyacrylonitrile with a Chelating Agent of
Triethanolamine and its EMI Shielding Effectiveness”, Thin
Solid Films, 517, 4984 (2009).
19. C. H. Lee and J. J. Kim, “Effects of Pd Activation on the Self-
Annealing of Electroless Copper Deposition using Co(II)–
Ethylenediamine as A Reducing Agent”, J. Vac. Sci. Technol.,
B23, 475 (2005).
20. M. Sone, K. Kobayakawa, M. Saitou and Y. Sato, “Electroless
Copper Plating using Fe as a Reducing Agent”, Electrochim.
Acta, 49, 233 (2004).
21. L. Yinxiang, “Electroless Copper Plating on 3-Mercaptopro-
pyltriethoxysilane Modified PET Fabric Challenged by Ultra-
sonic Washing”, Appl. Surf. Sci., 255, 8430 (2009).
22. I. Ohno, O. Wakabayashi and S. Haruyama, “Anodic Oxida-
tion of Reductants in Electroless Plating”, J. Electrochem.
Soc., 132, 2323 (1985).
23/ M. Cherkaoui, A. Srhiri and E. Chassaing, “Electroless Depo-
sition of Ni-Cu-P Alloys”, Plating Surf. Finish, 79, 68 (1992).
24. S. Armyanov, O. Steenhout, N. Krasteva, J. Georgieva, J. L.
Delplancke, R. Winand and J. Vereecken, “Auger Electron
Spectroscopy Element Profiles and Interface with Substrates
of Electroless Deposited Ternary Alloys”, J. Electrochem.
Soc., 143, 3692 (1996).
25. F. Florence, S. R. Nisha, K. N. Srinivasan and S. John, “Stud-
ies on Electrodeposition of Copper from Methanesulphonic
Acid Bath”, Int. J. Chem. Tech. Research., 3(3), 1318 (2011).
26. M. Hasan and J. F. Rohan, “Cu Electrodeposition from Meth-
anesulfonate Electrolytes for ULSI and MEMS Applications”,
J. Electrochem. Soc., 157(5), D278 (2010).
27. Y. M. Lin and S. C. Yen, “Effects of Additives and Chelating
Agents on Electroless Copper Plating, Appl. Surf. Sci., 178,
116 (2001).
28. E. Norkus, A. Vaskelis and I. Stalnioniene, “Changes of the
Cu Electrode Real Surface Area during the Process of Elec-
troless Copper Plating”, J. Solid State Electrochem., 4, 337
(2000).
29. E. R. Pauliukait, G. Stalnionis, Z. Jusys and A. Vaškelis,
“Effect of Cu(II) Ligands on Electroless Copper Deposition
Rate in Formaldehyde Solutions: An EQCM Study”, J. Appl.
Electrochem., 36, 1261 (2006).
30. Regina Fuchs-Godec, Miomir G. Pavlovid and Milorad V.
Tomic, “The Inhibitive Effect of Vitamin-C on the Corrosive
Performance of Steel in HCl Solutions”, Int. J. Electrochem.
Sci., 8, 1511 (2013).
31. E. Norkus, K. Prusinskas, A. Vaskelis, J. Jaciauskiene, I. Stal-
nioniene and D. L. Macalady, “Application of Saccharose as
Copper(II) Ligand for Electroless Copper Plating Solutions”,
Carbohydr. Res., 342, 71 (2007).
32. K. Kondo, J. Ishikawa, O. Takenaka, T. Matsubara and M.J.
Irie, “Acceleration of Electroless Copper Deposition in the
Presence of Excess Triethanolamine”, J. Electrochem. Soc.,
138, 3629 (1991).
33. E. Norkus, A. Vaskelis, J. Jaciauskiene, J. Vaiciuniene, E.
Gaidamauskas and D. L. Macalady, “Environmentally Friendly
Natural Polyhydroxylic Compounds in Electroless Copper
Plating Baths: Application of Xylitol, D-Mannitol and D-Sor-
bitol as Copper(II) Ligands”, J. Appl. Electrochem., 35(1), 41
(2005).
34. T. Anik. M. E. Touhami, K. Himm, S. Schireen, R. A.
Belkhmima, M. Abouchane and M. Cissé, “Influence of pH
Solution on Electroless Copper Plating Using Sodium Hypo-
phosphite as Reducing Agent”, Int. J. Electrochem. Sci., 7,
2009 (2012).
35. X. Wu and W. Sha, “Experimental Study of the Voids in the
Electroless Copper Deposits and the Direct Measurement of
the Void Fraction Based on the Scanning Electron Micros-
copy Images”, Appl. Surf. Sci., 255, 4259 (2009).
36. F. Pearlstein and R. F. Weightman, Selective Electroless Cop-
per Deposition at a High Rate using Dimethylamine Borane
as a Reducing Agent”, Plating, 60, 474 (1973).
37. J. Meerakker and E. A. M. van den, “On the Mechanism of
Electroless Plating II. One Mechanism for Different Reduc-
tants”, J. Appl. Electrochem., 11, 395 (1981).
38. J. Meerakker, E.A.M. van den and J.W.G. de Bakker, On the
Mechanism of Electroless Plating. Part 3. Electroless Copper
Alloys”, J. Appl. Electrochem., 20, 85 (1990).
39. F. J. Nuzzi, “Accelerating the Rate of Electroless Copper Plat-
ing”, Plat. Surf. Finish., 70(1), 51 (1983).
40. M. Paunovic, “An Electrochemical Control System for Elec-
6Ashutosh Sharma, Chu-Seon Cheon and Jae Pil Jung
마이크로전자 및 패키징학회지 제23권 제4호 (2016)
troless Copper Bath”, J. Electrochem. Soc., 127, 365 (1980).
41. J. Duffy, L. Pearson and M. Paunovic, “The Effect of pH on
Electroless Deposition”, J. Electrochem. Soc., 130, 876 (1983).
42. S. Balci, A. M. Bittner, K. Hahn, C. Scheu, M. Knez, A.
Kadri, C. Wege, H. Jeske and K. Kern, “Copper Nanowires
Within the Central Channel of Tobacco Mosaic Virus Parti-
cles”, Electrochim. Acta 51, 6251 (2006).
43. L. Xu L. K. Zhou, H. Xu and L. Huang, “Copper Thin Coat-
ing Deposition on Natural Pollen Particles”, Appl. Surf. Sci.,
183, 58 (2001).
44. H. Y. Lee, A. Sharma, S. H. Kee, Y. W. Lee, J. T. Moon and
J. P. Jung, “Effect of Aluminium Additions on Wettability and
Intermetallic Compound (IMC) Growth of Lead Free Sn (2
wt.% Ag, 5 wt.% Bi) Soldered Joints”, Electron. Mater. Lett.,
10(5), 997 (2014).
45. Y.-S. Eom, J.-H. Son, H.-S. Lee, K.-S. Choi, H.-C. Bae, J.-
Y. Choi, T.-S. Oh and J.-T. Moon, “Development of Copper
Electro-Plating Technology on a Screen-Printed Conductive
Pattern with Copper Paste”, J. Microelectron. Packag. Soc.,
22(1), 51 (2015).
46. K. Son, M.-H. Choi, K. H. Lee, E. Byon, B.-H. Rhee and Y.-
B. Park, “Effects of Heat Treatment Conditions on the Inter-
facial Reactions and Crack Propagation Behaviors in Electro-
less Ni/electroplated Cr Coatings”, J. Microelectron. Packag.
Soc., 23(3), 69 (2016).
•Ashutosh Sharma
•Department of Materials Science and
Engineering, University of Seoul, Seoul-
02504, South Korea
•Research Interests: Pulse Electroplating,
Lead Free Soldering, Brazing, Metal Matrix
Nanocomposites
•Email: stannum.ashu@gmail.com
•Chu-Seon Cheon
•Danyang Soltec Co. Ltd., Hwaseong-si,
Gyeonggi-do, 445-861, Korea
•Research Interests: Solder Pastes, Lead Free
Soldering
•E-mail: zeuscheon@dyst21.co.kr
•Jae Pil Jung
•Department of Materials Science and
Engineering, University of Seoul, Seoul-
02504, South Korea
•Research Interests: Microjoining,
Electroplating, Brazing Fillers, Solder-Joint
Reliability, Metal Matrix Nanocomposites,
Lead Free Soldering
